Field of the Invention
The present invention relates to a cooling system, and more particularly, to a cooling system for an electronic rack.
Description of the Prior Art
FIG. 1 illustrates the thermal paths of a conventional cooling system 100 for an electronics rack, and the arrows denote the heat flows. Heat generated by heat sources 110 (electronic components equipped in the electronic equipment, e.g. IC or hard disk) is removed to the external environment 112 by the forced air circulation 111. Air is used as heat transfer media. For facilities like data centers, which house a lot of computer racks and associated components, an active cooling system 113 is needed in order to lower the temperature and increase the heat transfer capability of the circulated air. However, it is difficult to bring cold air into equipment effectively without fans and additional infrastructures.
An electronic rack can be filled easily by equipment with total power more 20 kilo-Watt today. The cooling infrastructure for such system requires very high air flow rate. It will take more area and power than electronic equipment. A good example is the energy efficiency of a data center. The common way to determine the energy efficiency of a data center is power usage effectiveness (PUE). This ratio is obtained with the total power delivered to the data center divided by the power used by equipment. The average PUE value of data centers is around 2. In other words, a data center with one Mega-Watt electronics equipment has to spend another Mega-Watt for the cooling system of the data center. Moreover, the conventional cooling system for an electronics rack is disadvantageous in that it is energy inefficient and causes enormous noises. The wear-out of moving parts of fans will also degrade the reliability of the overall system.
In view of the aforementioned disadvantages, the present invention provides a cooling system for an electronic rack characterized by no fans, low noises and low power consumption.